Urban Ecoist

I want to say yes here, but it really depends on what your bio-diesel is made from.

Researchers at the University of Illinois have tested various sources of bio-diesel and have determined that the best choices for bio-diesel and ethanol production that actually reduce the net carbon released into the atmosphere is …drumroll, please…perennial grasses.

The researchers analyzed published estimates of changes in soil organic carbon in landscapes converted from natural or agricultural land to biofuel crops.

They focused on corn, sugar cane, Miscanthus, switchgrass and native prairie grasses. They also evaluated the impact of harvesting and using corn stover (the plant debris left over after corn is harvested) as a cellulosic biofuel source.

Their analysis showed that converting native land (grassland or forest) to sugarcane dramatically reduced soil carbon, creating a carbon deficit that would take decades to repay. While perennial grasses add carbon to the soil each year, DeLucia said, it could take up to a century for the sugar cane to rebuild soil carbon to former levels on native land.

Harvesting the corn residue for cellulosic ethanol production also reduced the carbon in the soil. The more plant residue was removed, the more the soil carbon declined.

Planting perennial grasses on existing agricultural lands had the most beneficial effect on soil carbon, the researchers found. –SPX via Biofuel Daily

Maybe you have and maybe you have not heard that corn-based ethanol is not the wisest choice for biofuels. First, you have the issue that 20% of American-grown corn is being diverted into ethanol production, and that is corn that is not being consumed as food, by Americans or anyone for that matter. Most ethanol is produced from corn kernels, so it’s not like this is waste plant matter that would be tossed or composted anyway. No, this is food stuff that no one is eating, which means if there is less corn in the supply side of the economic equation, the price of corn has gone up. With the price of corn rising, more and more farmers (yes, especially the big corporate farms) are planting corn.

With more corn going into the limited amount of arable farmland available to the US, that means less of everything else being planted. So, we now have an issue with other food crops supplies decreasing — pushing up the prices of well, everything. Have you noticed the cost of a loaf of bread lately? Less wheat is being planted and the decreased supply leads to increased prices, even if demand were to remain steady.. which it won’t as more and more people join us on this wacky blue marble in space.

So, what kind of biofuels are okay, for all us urban ecoists that want to help the planet, live lightly, be kind and rewind our consumption practices, etc? The latest study, that is going to be published in next month’s Global Change Biology Bioenergy journal (try saying that three times fast), details that every time the Earth is plowed or dug up, that action releases carbon. Soil acts as a carbon sink, and that carbon is what makes soil good for crops. Plants really, um, dig carbon dioxide, remember?

Hmm, what “crop” needs no plowing, or at least not yearly plowing? Perennial prairie grasses. The grasses grow during the growing season, can be cut or harvested at the end of that season, and the plants spend the winter dormant, and then grow again the next season. No plowing, no seeding, and little to no fertilizer required.

How ironic that so many farmers spent years and years and years plowing under the native prairie grasses of the Great Plains, only to find that those perennial grasses just may save the US transportation fleet one day…

bio-diesel, University of Illinois, biodiesel, biofuel, biofuels, corn, ethanol, perennial grasses, prairie grasses, carbon, carbon dioxide, crops, farms, farming, wheat, prices, food supply, carbon sink, plowing